1. Field of the Invention
The present invention relates to vehicles, and particularly, to an electric-driven vehicle.
2. Description of the Related Art
Nowadays, vehicles have become transportation means indispensable in people's daily life, such as automobiles and motorcycles. However, in order to decrease the air pollution caused by vehicles, various electric-driven vehicles have been developing.
Chinese Patent No. ZL 02216290.9 disclosed a four-wheel electric-driven vehicle. It has a chassis frame, a handle frame, a seat, a rechargeable battery, two front wheels, and two rear wheels. The handle frame is operatively provided at a front end of the chassis frame. The seat is fixed at a rear end of the chassis frame. The front and rear wheels are rotatably mounted at opposite sides of the front and rear end of the chassis frame, respectively. The battery provides power supply for the vehicle. The electric-driven vehicle is steered by controlling the front wheels via the handle frame. This electric-driven vehicle is characterized in that two steering members are respectively provided at inner sides of the two front wheels, the handle frame is fixed on a top end of a front frame tube, which is operatively provided on the front end of the chassis, a projected portion is formed at a lower end of the front frame tube, and two link rods respectively have two first ends thereof pivotally connected with the projected portion via cardan joints and two second ends thereof pivotally connected with the steering members provided at the inner sides of the front wheels, whereby the front wheels are steerable via the link rods and the front tube by controlling the handle frame. However, the structure of the electric-driven vehicle allows only the front wheels steerable, but the rear wheels driven by the power supply not steerable. So, the movement tracks of the front and rear wheels are different in a veer. In this case, the rear, wheels may be obstructed while the front wheels may just pass by the obstruct, thereby leading to a low safety. Moreover, the electric-driven vehicle does not only occupy a large occupation area, but also unwieldy, un-collapsible and difficult for transportation. Furthermore, it is insecure for a rider during the running of the vehicle as it might be in a state with three wheels on the ground but one wheel hanging in the air when it is on the uneven ground due to the rigidity of the chassis frame.
Chinese Patent No. ZL 02109213.3 disclosed an electric-driven vehicle structure, as shown in FIG. 1. It has a supporting platform and a steering shaft pivotally connected with the supporting platform. Its two auxiliary wheels are respectively provided at opposite sides of a front end of the supporting platform, and an electric-driven wheel with smaller diameter is provided at a center of a rear end of the supporting platform and connected at a lower end of the steering shaft. A battery provided at the rear end of the supporting platform is electrically connected with a motor of the electrical driving wheel or the auxiliary wheels, so the electric-driven vehicle is able to move forward or backward. Additionally, the steering shaft is an extendable multi-section member, angle of which may be adjustable in forward, backward, upward, and downward directions. This electric-driven vehicle has a structure of two driving rear wheels and one steering front wheel may easily turnover in the driving, which leads to instability. Moreover, the battery is received in a raised portion in a middle of the platform of the vehicle. When a rider drives the electric-driven vehicle, he/she must stand on the platform by his/her feet at opposite sides of the raised portion, that is to say, the rider may not easy to get free from the vehicle, i.e. the rider is kept from getting rid of the vehicle by the raised portion of the vehicle in an emergency, such as a turnover of the vehicle, therefore, the rider may be injured in this case.
A two-wheel scooter-like personal mobility vehicle, Segway Human Transporter, was developed by Dean Kamen in December 2001. The Segway HT uses twin NiMH battery packs as its power supply, and five electric gyroscopes in order to keep constant balance of the vehicle. A rider may control the vehicle to move forward or backward or even stop by simply leaning the rider's body forward or backward, and may also turn the left handlebar to change the direction of the vehicle by changing the speed of the left and right wheels. When the wheels of the opposite sides respectively rotate in a reverse direction, the vehicle may turn around at the original point. This type of personal mobility vehicle came into the US market in March 2003, and had been sold for more than 6,000 sets in a short period. They firstly went into trade use and public use, for example, US Post Office, express companies, police offices, supermarkets, storehouses, and offices are their earlier consumers, and individual purchases existed either. The major advantage of Segway HT is that the occupancy area of the vehicle is less than one step walking area of a person (width of both are equal, but the length of Segway HT is less than one step length of an adult). Therefore, it can be used in various circumstances including indoors, as for examples, passing through corridors and entering elevators etc. One disadvantage of the Segway HT is that the vehicle is only movable on a plan and smooth ground surface, if there are any obstacles on the way in front of the wheels of the vehicle, the rider standing on the supporting platform of the vehicle would certainly incline forward due to the inertia, while it is not possible for the electric gyroscopes to response and keep the whole vehicle in balance immediately. Three persons had been injured since Sep. 27th, 2003, the US Consumer Product Safety Commission (CPSC) declared that they had asked Segway LLC to recall all the sold products for the safety reason. Furthermore, the operation of Segway HT is complex, and it even takes a US policeman a whole day to train how to ride and control the vehicle.
Therefore, there is a necessary to provide an improved electric-driven vehicle, which has not only most advantages of the prior art, but also further advantages of more steady stability, more simple structure, better steering agility, more easy to be transported and can be operated in both indoor and outdoor conveniently in comparison with electric-driven vehicles of the prior arts, such as Segway HT.
Furthermore, a supporting structure is needed to provide to the electric-driven vehicle, which employs a flexible structure, solving the problem of one wheel hanging in the air when on the uneven ground.